Multi-tubular chemical reactor with igniter for initiation of gas phase exothermic reactions

Abstract

A multi-tubular chemical reactor includes an igniter for the initiation of gas phase exothermic reaction within the gas phase reaction zones of the tubular reactor units. In accordance with the present disclosure, there is provided a multi-tubular chemical reactor comprising a plurality of spaced-apart reactor units, each reactor unit comprising an elongate tube having a wall with internal and external surfaces, an inlet at one end and an outlet at the opposing end, the wall enclosing a gaseous flow passageway at least a portion of which defines a gas phase reaction zone, the multi-tubular chemical reactor can include at least one igniter for initiation of at least one gas phase exothermic reaction within a gas phase reaction zone of a reactor unit.

The invention claimed is: 
     
       1. A multi-tubular chemical reactor comprising:
 a plurality of spaced-apart reactor units aligned in a single row or parallel rows of essentially identical configuration aligned along a common longitudinal axis corresponding to line L of length X, line L extending from the first to the last reactor disposed within a row, each reactor unit in a row comprising an elongate tube having a wall with internal and external surfaces, an inlet at one end and an outlet at the opposing end, the wall enclosing a gaseous flow passageway at least a portion of which defines a gas phase reaction zone; and 
 at least one igniter for the initiation of a plurality of gas phase exothermic reactions within the gas phase reaction zones of the reactor units, the igniter including a radiant heat-producing element positioned in proximity to, but in physical isolation from, exposed sections of reactor units, the length of such heat-producing element extending from at least about 30 percent up to about 100 percent of length X of line L. 
 
     
     
       2. The multi-tubular chemical reactor of  claim 1  wherein the multi-tubular chemical reactor is a partial oxidation reformer or autothermal reformer. 
     
     
       3. The multi-tubular chemical reactor of  claim 1  wherein the maximum distance between adjacent reactor units during a steady-state mode of operation is that distance beyond which the temperature of the plurality of spaced-apart reactor units falls below a predetermined minimum array temperature value; and the minimum distance between adjacent reactor units is that distance below which the temperature at an outlet of a reactor unit is greater than a predetermined maximum temperature value. 
     
     
       4. The multi-tubular chemical reactor of  claim 1 , further comprising at least one thermocouple disposed within a chamber comprising the plurality of spaced-apart reactor units. 
     
     
       5. The multi-tubular chemical reactor of  claim 1  comprising a plurality of igniters, at least one igniter being disposed at one end of a chamber comprising the plurality of spaced-apart reactor units and at least one igniter being disposed at the opposite end of the chamber. 
     
     
       6. The multi-tubular chemical reactor of  claim 1  comprising a plurality of igniters and a plurality of thermocouples disposed within a chamber comprising the plurality of spaced-apart reactor units, wherein at least one igniter and at least one thermocouple are disposed at one end of the chamber and at least one igniter and at least one thermocouple are disposed at the opposite end of the chamber. 
     
     
       7. The multi-tubular chemical reactor of  claim 6  wherein the plurality of igniters and the plurality of thermocouples are disposed within the chamber such that at least one igniter at one end of the chamber is opposite a thermocouple at the opposite end of the chamber. 
     
     
       8. The multi-tubular chemical reactor of  claim 1  comprising a source of gaseous reactants, the source of gaseous reactants in fluid communication with the gas phase reaction zone(s) of the reactor unit(s). 
     
     
       9. The multi-tubular chemical reactor of  claim 1  comprising a controller for controlling the operation of the multi-tubular chemical reactor, the controller in operative communication with the at least one igniter, and if present, at least one of the at least one thermocouple and the source of gaseous reactants. 
     
     
       10. A multi-tubular chemical reactor comprising:
 a plurality of spaced-apart reactor units, each reactor unit comprising an elongate tube having a wall with internal and external surfaces, an inlet at one end and an outlet at the opposing end, the wall enclosing a gaseous flow passageway at least a portion of which defines a gas phase reaction zone; and 
 at least one igniter for the initiation of a plurality of gas phase exothermic reactions within the gas phase reaction zones of the reactor units, the igniter including a radiant heat-producing element positioned in proximity to, but in physical isolation from, exposed sections of reactor units, the length of such heat-producing element extending from at least about 60 percent up to about 100 percent of length X of line L. 
 
     
     
       11. The multi-tubular chemical reactor of  claim 10  wherein the multi-tubular chemical reactor is a partial oxidation reformer or autothermal reformer. 
     
     
       12. The multi-tubular chemical reactor of  claim 10  wherein the maximum distance between adjacent reactor units during a steady-state mode of operation is that distance beyond which the temperature of the plurality of spaced-apart reactor units falls below a predetermined minimum array temperature value; and the minimum distance between adjacent reactor units is that distance below which the temperature at an outlet of a reactor unit is greater than a predetermined maximum temperature value. 
     
     
       13. The multi-tubular chemical reactor of  claim 10  further comprising at least one thermocouple disposed within a chamber comprising the plurality of spaced-apart reactor units. 
     
     
       14. The multi-tubular chemical reactor of  claim 10  comprising a plurality of igniters, at least one igniter being disposed at one end of a chamber comprising the plurality of spaced-apart reactor units and at least one igniter being disposed at the opposite end of the chamber. 
     
     
       15. The multi-tubular chemical reactor of  claim 10  comprising a plurality of igniters and a plurality of thermocouples disposed within a chamber comprising the plurality of spaced-apart reactor units, wherein at least one igniter and at least one thermocouple are disposed at one end of the chamber and at least one igniter and at least one thermocouple are disposed at the opposite end of the chamber. 
     
     
       16. The multi-tubular chemical reactor of  claim 15  wherein the plurality of igniters and the plurality of thermocouples are disposed within the chamber such that at least one igniter at one end of the chamber is opposite a thermocouple at the opposite end of the chamber. 
     
     
       17. The multi-tubular chemical reactor of  claim 10  comprising a source of gaseous reactants, the source of gaseous reactants in fluid communication with the gas phase reaction zone(s) of the reactor unit(s). 
     
     
       18. The multi-tubular chemical reactor of  claim 10  comprising a controller for controlling the operation of the multi-tubular chemical reactor, the controller in operative communication with the at least one igniter, and if present, at least one of the at least one thermocouple and the source of gaseous reactants. 
     
     
       19. A method of initiating a gas phase reaction in the chemical reactor of  claim 1  having at least 3 igniters, comprising the steps of:
 initiating maximum heating in all of the igniters; 
 determining initiation of a gas phase exothermic reactions within centrally located reactor units; 
 reducing heating of outer igniters to a first heating level; 
 reducing heating of inner igniters to a second heating level, the second heating level being less than the first heating level; 
 determining initiation of a gas phase exothermic reactions within outer located reactor units; and 
 turning off the heating of the igniters.